1. Field of the Invention
This invention relates to a camera with a barrier, and more particularly to a camera with a barrier wherein an exposure controlling mode is automatically changed over in response to an opening or closing motion of the barrier which is provided to cover an operating member for exposure operation when there is no necessity of operation of the operating member.
2. Description of the Prior Art
Recent cameras include a built-in controlling circuit and have operation keys for inputting data to the controlling circuit. Cameras have been already proposed wherein such operation keys are arranged depending upon the frequency in use and an openable and closable cover is provided to cover those operation keys which are not used very frequently. A typical one of such cameras is disclosed, for example, in Japanese Patent laid-open No. 58-136019. However, the prior art arrangement is not constituted such that a controlling mode of an exposure controlling circuit of a camera is changed over in response to an opening or closing motion of the cover.
Meanwhile, cameras having a lens cover which is actuated to open and close a camera lens are on the market, and a camera has been proposed wherein operation thereof is enabled when such a lens cover is opened but when the lens cover is closed, operation of the camera is disabled. However, the proposed camera does not allow change-over of a controlling mode of an exposure controlling circuit of the camera in response to an opening or closing motion of the lens cover.
It is troublesome for a photographer to take various matters into consideration over exposure in preparation for photographing. Accordingly, it is convenient to photograph with programmed exposure which is normally equipped as a standard for a camera. However, in some cases, it may become necessary to photograph with an effect of at least either one of a shutter speed and an aperture value taken into consideration.
Accordingly, a single-lens reflex camera is constituted to allow change-over among programmed exposure in which there is no necessity of taking anything into consideration over exposure, and an A mode (aperture priority exposure), an S mode (shutter speed priority exposure) and an M mode (manual exposure) in which intention of a photographer can be reflected on exposure. By the way, change-over members for such change-over operation are exposed outside a camera. Accordingly, if the camera is used to photograph with those change-over members operated inadvertently, photographing will be conducted in any other mode than the programmed exposure. Consequently, the exposure time may become too long, resulting in failure of a photograph due to a shake of the camera, or the aperture value may be improper, resulting in failure of a photograph wherein the depth of field is either too deep or too shallow or wherein exposure is not proper. Thus, it is a problem that an unexpectedly failed photograph may be produced. Further, in case of a beginner photographer, it is another problem that an intended photograph may not be taken due to a fact that the camera is operated before the photographer understands how to reflect his or her intention on exposure.